4.5★s Cast Iron is the sixth book in the Enzo Macleod Investigation series by Scottish journalist, screenwriter and author, Peter May. After refreshing himself on the details of Roger Raffin’s sixth cold case with him, Enzo heads in the direction of Bordeaux to meet the parents of Lucie Martin, whose unexplained disappearance in 1989 became a murder case when a nearby lake dried up during the drought of 2003, revealing her skeleton. But not long after meeting the Martins, Enzo feels ambushed when he finds himself in the middle of a gathering of the families of six young women who are missing or dead, all of whom believe a certain killer of three prostitutes is to blame. While a letter from pimp Régis Blanc was found in Lucie’s bedroom, he has a cast iron alibi for when she disappeared. Enzo talks to Lucie’s boyfriend, the ex-cop whom the families of the Bordeaux Six hired to investigate, Blanc’s wife and the women he pimped. He locates Lucie’s missing skull and makes a discovery that changes the whole complexion of the case. The more he hears, the less he is convinced that Blanc is Lucie’s killer. When he meets Blanc in Lannemezan Prison, he becomes intrigued by the motive for the three murders for which this enigmatic man was incarcerated. But then he is distracted by his younger daughter. And in the crisis that follows, Enzo, true to form, has four women falling over themselves to assist in any way they can. Sophie and her fiancé Bertrand discover first-hand just how dangerous being beloved of Enzo can be when his investigations displease certain people. Bertrand certainly gets a chance to prove his love, and Sophie shows herself to be resourceful and undefeated by challenging circumstances. In what feels like the final book in the series, the action ranges from Paris to Cahors to Bordeaux to Biarritz. Some clever deduction and plenty of legwork is done, and there are plenty of twists and red herrings before the shocking reveal of just who is trying to kill Enzo, and why. Both of Roger Raffin’s remaining cold cases are solved and loose ends are tied in a fairly neat bow, so fans of the series will doubtless be interested to know what May has planned for Enzo and crew in the seventh book of the series, The Night Gate. Enjoyable crime fiction.